When in doubt, write a Web page....
I have written up a Web page for the Last Call on
http://domen.uninett.no/apps/last-call/mime-draft2.html
and attached a text version to this document.
Given the debate that has occured, I regard the question of
multipart/alternative as settled, while there is still missing evidence for
multipart/parallel, generation of nested body parts and handling of external
body parts.
When new evidence arrives (on this list, please!), I will update the Web page.
Harald T. Alvestrand
Apps AD
LAST CALL FOR MIME DOCUMENTS TO RECYCLE AT DRAFT
The following Last Call has been issued:
The IESG has received a request to consider the following Protocol
Actions:
1. Multipurpose Internet Mail Extensions (MIME) Part One: Format of
Internet Message Bodies" for the
status of Draft Standard.
2. Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types
for the status of Draft
Standard.
3. MIME (Multipurpose Internet Mail Extensions) Part Three: Message
Header Extensions for Non-ASCII Text
for the
status of Best Current Practice.
5. Multipurpose Internet Mail Extensions (MIME) Part Five: Conformance
Criteria and Examples for the
status of Draft Standard
The IESG plans to make a decision in the next few weeks, and solicits
final comments on this action. Please send any comments to the
iesg(_at_)ietf(_dot_)org or ietf(_at_)ietf(_dot_)org mailing lists by August 8,
1996.
No objections to the Last Call were received before August 8.
After the timeout date for the Last Call comments, the following
issues with regard to implementation experience have been raised:
* Is multipart/alternative widely implemented for generation?
* Is multipart/alternative widely implemented for reception?
* Is multipart/parallel widely implemented?
* Are Nested Body Parts widely implemented?
* Are External Body Parts widely implemented?
The issue here is if the "two implementations" rule (which
traditionally have allowed two experimental implementations without
terribly useful user interfaces) should be strengthened for a
specification of this maturity to mean "two interworking, commercial
implementations that can be used by someone not terribly skilled in
the arcana of MIME".
The sections below will give the arguments and evidence in each case.
Is multipart/alternative widely implemented for generation?
The question is if there exist MUAs that can generate a MIME
multipart/alternative without excessive thinking on the part of the
user.
The following MIME UAs have been claimed to do so:
* Cyberdog for the Macintosh
* Ishmail
* An yet-unnamed product from Microsoft
This AD regards the question as settled.
Is multipart/alternative widely implemented for reception?
The question is if there exist UAs that display the "best" body part
(that being defined as the last part of the multipart/alternative that
the UA is able to display).
The following UAs have been claimed to do so:
* Pine
* Metamail
* Mac Eudora 3.0
This AD regards the question as settled.
Is multipart/parallel widely implemented?
The question is if there are UAs that display all parts of the
multipart/parallel "at the same time", as described in the drafts, and
do not jsut treat it like multipart/mixed, and if there are generating
UAs.
To date, no generating UA has been identified.
To date, only Metamail has been mentioned as an example of a
displayer.
Are Nested Body Parts widely implemented?
Many MUAs work according to the "one message with attachments"
metaphor, which is not the same as the MIME "bodyparts may nest to any
level" structure. Forwarded messages are not part of this question.
One may argue that the "inline/attachment" distinction that is carried
in content-disposition is missing functionality in MIME. However,
content-disposition is the subject of another ongoing action, and will
have to catch up later.
The question is if there exist MUAs that:
1. Generate nested multiparts through a reasonable user interface
2. Usefully display nested multiparts
The following MUAs have reasonable support for generating nested
multiparts:
*
The following MUAs have reasonable support for displaying nested
multiparts:
* EXMH 1.6.7
Are External Body Parts widely implemented?
The question is if there exist MUAs that:
1. Generate External Body Parts through a reasonable user interface
2. Usefully handle External Body Parts
The IETF internet-drafts announcement uses multipart/alternative with
external body parts to list the ways in which one can get the I-Ds.
This is special purpose code, and only proves that such messages can
be generated.
The following MUAs have reasonable support for generating External
Body Parts:
*
The following MUAs have reasonable support for handling External Body
Parts:
* MH 6.8.3
_________________________________________________________________
Harald(_dot_)T(_dot_)Alvestrand(_at_)uninett(_dot_)no
Last modified: Sat Aug 17 09:32:26 1996